round/Objective: The objective of this clinical trial is to evaluate the clinical efficacy of a resin infiltrant (Icon®, DMG) compared to an ionomer-based fluoride varnish (Clinpro XT®, 3M) in preventing post-eruptive enamel breakdown (PEB) in permanent molars with mild Molar Incisor Hypomineralization (MIH).

Research Question: Can resin infiltration effectively prevent post-eruptive enamel breakdown in permanent molars with mild MIH compared to an ionomer-based fluoride varnish? Methodology: The researchers will compare the resin infiltrant Icon® (DMG) with Clinpro XT® Varnish (3M) to prevent post-eruptive enamel breakdown in permanent molars with mild MIH.

Participants:

Children aged 6 to 13 years presenting at least two permanent molars affected by mild MIH, with no prior structural loss or previous dental treatment.

Requirement to attend follow-up evaluations at 15 days, 1 month, 3 months, and 6 months.

Inclusion Criteria:

• Participants with two or more permanent molars affected by mild Molar Incisor Hypomineralization (MIH), graded according to EAPD criteria.
• Mild MIH-affected permanent molars with no history of prior dental treatment.
• Fully erupted or partially erupted permanent molars
• Permanent molars with MIH presenting ICDAS code 0, 1, or 2 (non-cavitated caries lesions).
• Systemically healthy patients.
• Patients (and/or legal guardians) who agree to participate, providing written informed consent and child assent.

Exclusion Criteria:

• Presence of only one permanent molar affected by MIH.
• Permanent molars with MIH that already present post-eruptive breakdown (PEB).
• Permanent molars with caries lesions classified as ICDAS 3 or higher.
• Enamel defects of other etiologies in permanent molars (e.g., Amelogenesis Imperfecta, fluorosis, or hypoplasia).
• Patients with systemic diseases or lack of cooperation during dental treatment